mmc: sdhci-s3c: Do not allow frequencies higher than requested

This patch modifies sdhci_s3c_consider_clock() to fail if bus clock
being considered can not provide frequency lower or equal requested,
instead of returning the lowest supported.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Acked-by; Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Chris Ball <chris@printf.net>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
index bad0e00a3e8f..d61eb5a70833 100644
--- a/drivers/mmc/host/sdhci-s3c.c
+++ b/drivers/mmc/host/sdhci-s3c.c
@@ -126,11 +126,18 @@ static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
 
         rate = ourhost->clk_rates[src];
 
-        for (shift = 0; shift < 8; ++shift) {
+        for (shift = 0; shift <= 8; ++shift) {
                 if ((rate >> shift) <= wanted)
                         break;
         }
 
+        if (shift > 8) {
+                dev_dbg(&ourhost->pdev->dev,
+                        "clk %d: rate %ld, min rate %lu > wanted %u\n",
+                        src, rate, rate / 256, wanted);
+                return UINT_MAX;
+        }
+
         dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
                 src, rate, wanted, rate >> shift);